Electrode Architectures for High power density Li-ion batteries - - PowerPoint PPT Presentation

Electrode Architectures for High power density Li-ion batteries

Electrode Architecture

Electrochemical Testing

1 2 3 4 2 4 6 8 10 Number of Active Material Layers Active Material Loading (mg/cm

2)

0.2 0.4 0.6 0.8 1.0

Discharge Capacity Active Material Loading

Discharge Capacity (mAh/cm

2)

10 20 30 40 50 20 40 60 80 100 120

One, 2.4 mg/cm

2

Four, 8.93 mg/cm

2

Std, 2.76 mg/cm

2

Discharge Capacity (mAh/g) C-Rate

Uniform Increase in loading Had minimal impact on the C‐rate

Effect of Electrode composition

2 4 6 8 10 12 14 16 18 20 22 20 40 60 80 100 120

Std, 10% carbon 1.85 mg/cm

2

Std, 20% carbon 2.76 mg/cm

2

4 Layer, 10% carbon 7.19 mg/cm

2

4 Layer, 20% carbon 6.18 mg/cm

2

Discharge Capacity (mAh/g) C-rate

With low rate material

2 4 6 8 10 12 3 6 9 12

4 Layer, 9.1 mg/cm

2

Std, 6.5 mg/cm

2

Power Output (mW/cm

2)

Energy Output (mWh/cm

2)

100 200 300 400 500 50 100 150 200 250

4 Layer, 9.1 mg/cm

2

C/20 C/20 1C 1C 1C C/20

Discharge Capacity (mAh/g) Cycle Number

Layered‐ layered Oxide active material

Comparision

Energy Harvesting from Infrared Sources

Need

• Needs a continuous source of energy for

various electronics, communication and sensing devices.

• Need to carry less heavy batteries and

reduce the warfighter’s load.

• Other energy harvesters are either heavy or

cannot provide the needed power.

• Thin film organic photovoltaic cannot

provide power in the absence of sunlight (e.g. nighttime cloudy days etc.).

Modern day smart soldier

 A light weight flexible device capable of harvesting energy continuously and producing enough power to properly power various portable devices.

Objectives & Advantages

Objectives:

• To harvest energy at any time even

in the absence of sunlight.

• To harvest energy from any heat

source

• To harvest energy from sunlight

complementing solar cells.

Advantages:

• Extremely lightweight
• Flexible
• Easily incorporated into fabrics
• Low manufacturing cost

Application:

• Remote operations
• Emergency situations
• Stand alone operations

Sources of infra red

Daytime sunlight Human Body Vegetation Nighttime Microprocessor Manmade

Infra red Antenna – Barriers

Antenna:

• Excellent resonance (>80%) in the desired

frequency range (300GHz-450THz )

• Choice of materials need to exhibit very low

electronic transition when coupling to the incident photon (reduced loss)

• Needs Nano-micro scale features to address the

desired frequency range

• Low electron phonon coupling (low heat generated)

Rectifier circuit:

• Needed diodes operating in the 300GHz-450THz range with efficiency >80%

 There are no diodes available commercially in that range.  Research efforts are very limited.

• Low cost manufacturing method to address cost effectiveness.

Coupling circuit:

• Needed to have ~90% coupling efficiency.
• Current couplers have not been tested in the desired frequency range

How Does it Compare with Thermoelectric Harvester

Power generated (W/m2)

Temperature Difference (C)

Assumptions:

• Sink is at room temperature
• (20 C)
• Area of coverage for the rectenna: 60%
• Area of coverage for the Thermo-

electric: 100%

• Load resistance: 250 Ohms

Using diodes with theoretical limit (80% efficiency) Using diodes in research ( 30% efficiency) Using commercially available W band diodes(10% efficiency) Thermoelctric

10 20 30 40 50 60 70 80 90 100 10 20 30 40 50 60 70 Thermoelectric Rectenna Series3 Series4

Design & Simulation

Antenna Fabrication

Fluidic assembly is employed

Testing with Commercial W band (30GHz) diodes

Circuit employed Testing setup

 Energy harvested was several hundreds of Nano watts